Automatic spring-pressed needle expansion valve



Nov. 25, 1952 w. .1. PRITCHETT AUTOMATIC SPRING-PRESSED NEEDLE EXPANSION VALVE Filed NOV. 21, 1951 1w Z 1 3 I m IIIIIIY7/l/l77 //l- WJPriZcheZi ATTORNEYS fiatented Nov. 2 5, 1952 OFFICE AUTOMATIC SPRING-FEES1 SED' NEEDLE EXPANSION VALVE William -J.-Pritchett, Demopolis, Ala. Application November 21, 11951, Serial No; 257,513

2' Claims. 1

This invention-relates to improved expansion valve.

A-n object' of this inventionis to provide-an improvedexp'an'sionyalve which can be readily adjusted as to its operating cycles without removing or exposing any operating parts of the valve to the outside atmosphere andis-Ieak-proof.

Another object 'of this invention is toprovide an expansion-valve which includes a valve housing-having a spring-pressed needle valve-"therein which is' norma-lly' biased to'an open position, theneed-le valve being engaged by a; resilient saddle which is spring-pressed to a bowed valve releasing position by means of a tensioned bellows which is sealed relative to the housing. The tension of thebellows ismanually adjusted so as to provide fortheselective opening and closing of the needle valve.

With the above and other objects in view; my invention consists in the arrangement, combination and details of'con'struc-tion disclosed in the drawings and specification, and then more .particularly pointed out in the appended claims.

In the drawing:

Figure 1 across section of an expansion valve constructed according to an embodiment of this invention.

Figure 2 is a fragmentary sectional view taken on the line 2-2 of Figure 1.

Referring to the drawing, the numeral I designates generally a cylindrical housing having a bore II which forms a pressure chamber I2. A nipple or connector I3 is threaded through the side of the housing I9 and is formed with a bore I4 which constitutes the outlet port for the housing [0. A diametrically disposed nipple or fitting I5 is threaded into the housing II] and is formed at its inner end with an internally threaded bore I6 within which a valve seat member I1 is threaded. The valve seat member I1 is formed with a seat I8 against which a needle valve I9 is adapted to engage. The needle valve I9 is formed at its inner end with an enlarged head 29 against which the inner end of an expansion spring 2| engages, and the outer end of the spring 2| engages against the seat member I1 and constantly urges the needle valve I9 to an open position.

A screen or filter member 22 is disposed in a counterbore 23 formed in the fitting I5 so as to filter the fluid passing into the valve housing II). The fitting I5 forms the intake fitting and is adapted to be connected to a source of fluid pressure supply. The housing In is formed with a counterbore 24 extending from one end of the bore or chamber I2, and the outer end of the counterbore 24- is defined by annular inwardly extending rib or flange'2-5L The 'hoi'ising It] also includes 'a second coiinterbore 2'6; islarger in I diameter than the" connterbore 242 A resilient and expansi-ble-bellows "2 1 is di 'spos' partly within the counterbore 26 and p tly within the counterbore 24. The bellows Z1 is sea-led by meansof'solder; welding; or the like indicated at- 2 8 being securedand sealedto the flange or rib '25. As shown in F gure I of the drawing, a minor portionof the bellows? 21 is disposed within the coun -terbore 2'4' whereas 't e major portionof'the' bellows '21 disposed with the'counterbore 26.- The-bellows fl includes arr inner head or plate 29 which is sealed-relative to the'b'ellows and the' head' or pl'ate 29 has fixed; thereto a plug 39--fo-rmed with a-conical ear 3] 2 i The outerendof the-bellowsifl is close by meanslof a 'plate32 "and asecond plate '33 Sir stantiall'y heavier than the plate- 32', -i's-- fix the outer side of plate 3 2. A-bellow s tens spring 34 is disposed -'-with1n the bellow -2 1 mg against theinner-side's of plates 29 i A bellows tensioning cap 35- is threaded-- about the housing 19' and-includes-ahead 36*beari'rig against the plate 33. Inward threading of the cap 35 will tension spring 34 and bellows 21. A plug 31 is threaded into the housing I0 closing the end of chamber I2 oppositely from bellows 21.

Plug 31 is formed with a conical seat 38 at a point horizontally aligned with conical seat 3I and a resilient fiat spring 39, formed with pointed opposite ends 40 and M, is disposed between the plug 39 and the plug 31 with the ends 40 and M seated in the seats 3I and 38.

The spring or valve operator 39 extends lengthwise of chamber I2 and engages beneath the head 20 of the inner end of needle valve I9. When pressure in chamber I2 is of a predetermined degree, bellows 21 will contract and spring or valve operator 39 will straighten out and will overcome tension of spring 2I so as to thereby move needle valve I9 to a closed position. When pressure in chamber I2 decreases to a predetermined degree, bellows 21 will expand and spring 34 will cause spring 39 to bow away from needle valve I9, thereby releasing tension of spring 39 on needle valve l9 and permitting spring 2| to move needle valve I9 inwardly to an opened position. When pressure builds up in chamber I2, that portion of bellows 21 which projects into the counterbore 24 will be compressed, thereby permitting spring or valve o erator ,39 to straighten out toward its normal straight condition, and valve l9 will then be move to a closed position.

In view of the fact that needle valve I9 is forced open or closed by spring tension, the valve will operate accurately in any position, and the fact that the bellows is sealed at each end by the plates 29 and 32, the fluid passing through the valve housing will not enter the bellows or cause a corroding on the inside thereof which might affect the operation of the bellows and the tension of bellows operating spring 34, nor-allow any moisture or other foreign matter to enter the bellows which would also affect the operation of the bellows and the tension of bellows operating all variations falling within the purview of the:

appended claims.

What is claimed is: 1. "An expansion valve comprising a housing having a chamber therein, inlet and outlet connectors communicating with said chamber, an inwardly opening needle valve carried by said inlet connector, a springnormally urging said needle valve to open position, said housing havinga counter-bore extending from said chamber, an annular flange at the outer end of said counter-bore, said housing also having a second counter-bore extending outwardly of said flange, a bellows fixed to said flange and disposed partly inone counter-bore and partly in the other counter-bore, end plates fixed to and closing the opposite ends of said bellows, an expansion spring disposed between said end plates, a recessed plug fixed to the inner one of said end plates, a threaded plug carried by said housing oppositely from said bellowsand formed with a recess confronting said first named recess, a flat resilient valve operator seated at the opposite ends thereof in said recesses and extending across the inner end of said needle valve, and a cap threaded on said housing bearing against the outer one of said end plates for tens ioning said second spring and said operator, pressure in said chamber beyond file of this patent:

4 a predetermined degree compressing the inner portion of said bellows and permitting said operator to move said needle valve to a closed position against the tension of said first named spring.

2. An expansion valve comprising a housing having a chamber therein, inlet and outlet connectors communicating with said chamber, an inwardly opening needle valve carried by said inlet connector, a spring normally urging said needle valve to open position, said housing having a counter-bore extending from said chamber, an annular flange at the outer end of said counter-bore, said housing also having a second counter-bore extending outwardly of said flange, a bellows fixed to said flange and disposed partly in one counter-bore and partly in the other counter-bore, end plates fixed to and closing the opposite ends of said bellows, an expansion spring disposed between said end plates, a recessed plug fixed to the inner one of said end plates, a

threaded plug carried by said housing oppositely from said bellows and formed with a recess 0011-: fronting said first named recess, a flat resilient valve operator seated at the opposite ends thereof in said recesses and extending across the inner end of said needle valve, a wear plate fixed to the outer on of said end plates, and a cap threaded on said housing bearing against said wear plate for tensioning said secondspring and said operator, pressure in said chamber beyond a predetermined degree compressin the inner portion of said bellows and permitting said operator to move saidneedle valve to a closed position against the tension of said first named spring.

WILLIAM J. PRITCHETT. I

REFERENCES CITED The following references are of record in the UNITED STATES PATENTS 

